Physical durability and insecticidal activity of long-lasting insecticidal nets in Cruzeiro do Sul, Brazil.

Vector control is one of the principal strategies used for reducing malaria transmission. Long-lasting insecticidal bed nets (LLINs) are a key tool used to protect populations at risk of malaria, since they provide both physical and chemical barriers to prevent human-vector contact. This study aimed to assess the physical durability and insecticidal efficacy of LLINs distributed in Cruzeiro do Sul (CZS), Brazil, after 4 years of use. A total of 3000 LLINs (PermaNet 2.0) were distributed in high malaria risk areas of CZS in 2007. After 4 years of use, 27 'rectangular' LLINs and 28 'conical' LLINs were randomly selected for analysis. The evaluation of physical integrity was based on counting the number of holes and measuring their size and location on the nets. Insecticidal efficacy was evaluated by cone bioassays, and the amount of residual insecticide remaining on the surface of the LLINs was estimated using a colorimetric method. After 4 years of use, physical damage was highly prevalent on the rectangular LLINs, with a total of 473 holes detected across the 27 nets. The upper portion of the side panels sustained the greatest damage in rectangular LLINs. The overall mosquito mortality by cone bioassay was < 80% in 25/27 rectangular LLINs, with panel A (at the end of the rectangular bednet) presenting the highest mortality (54%). The overall mean insecticide concentration was 0.5 µg/sample, with the bednet roof containing the highest average concentration (0.61 µg/sample). On the conical LLINs, 547 holes were detected, with the bottom areas sustaining the greatest damage. The cone bioassay mortality was < 80% in 26/28 of the conical LLINs. The mean insecticide concentration was 0.3 µg/sample. After 4 years of use, the insecticidal efficacy of the LLINs was diminished to below acceptable thresholds.

Phylogeny of Anopheles darlingi (Diptera:Culicidae) based on the antimicrobial peptide genes cecropin and defensin.

Cecropins and defensins are the main classes of antimicrobial peptides in the mosquito innate immune system, acting against bacteria, fungi and protozoa. There is a knowledge gap concerning these peptide genes in anopheline mosquitoes from the Brazilian Amazon. Thus, this work aimed to describe molecular techniques for detecting the genes encoding the antimicrobial peptides cecropin A (CecA) and defensin in Anopheles darlingi mosquitoes and to perform molecular phylogeny of the sequenced genes using the maximum likelihood method and Bayesian inference with other species from different geographic areas. Our results show, for the first time, a molecular biology method for detecting CecA and defensin in Anopheles darlingi that allows for the use of these molecular markers for phylogenetic analysis in anopheline species, separating the species into single and monophyletic clades.

Morphological identification of species of the Nuneztovari Complex of Anopheles (Diptera: Culicidae) from an area affected by a Brazilian hydroelectric plant.

The Nuneztovari Complex of Anopheles (Diptera: Culicidae) comprises four species: An. nuneztovari Gabaldon, An. goeldii Rozeboom Gabaldon, An. dunhami Causey and An. nuneztovari species A. This study aimed to identify morphologically the species of the Nuneztovari Complex that occur in the area of the Belo Monte hydroelectric dam. The morphological identification of adult males and male genitalia (aedeagus and ventral claspette) was performed. A statistical analysis of the difference in aedeagal leaflet length was done using the Mann-Whitney test. Of the 38 male genitalia of specimens of the Nuneztovari Complex examined, 33 were identified as An. goeldii/An. nuneztovari A and five as An. nuneztovari s.s. A statistically significant difference in aedeagal leaflet length was detected between the species: the mean length was 1.23 µm for An. goeldii/An. nuneztovari A and 9.18 µm for An. nuneztovari s.s. This is the first record of An. nuneztovari s.s.in areas of environmental modification in the Brazilian Amazon. This study provides a measurement tool that can identify and differentiate species of the complex in the region, which can be applied to the other species of the complex as well to other anopheline species; thus, fostering the acquisition of information about the role of each species in malaria transmission.

VK210 and VK247 genotypes of Plasmodium vivax in anopheline mosquitoes from Brazilian Amazon.

Plasmodium vivax sporozoites are differenced by circumsporozoite protein. Studies on the circulation of P. vivax VK210 and P. vivax VK247 in anopheline mosquitoes are important to verify the adaptability of these parasites on mosquitoes in different locations and periods. This study aimed to describe and compare the distribution of these genotypes in anopheline mosquitoes from four states of the Brazilian Amazon. Epidemiological databases about CSP infections on mosquitoes from Pará (2000-2015), Amapá (2000-2010), Roraima (2000-2003 and 2009-2011) and Acre States (2012-2015) were used for analysis. A total of 895 specimens were found infected mainly by P. vivax VK210. We showed that the distribution of P. vivax VK247 changed over time in the main malaria vectors on the Brazilian Amazon. We note that A. darlingi was abundant in certain localities while A. albitarsis s.l. in anothers, which highlights the importance of entomological studies for the control of human malaria.

Epidemic and Non-Epidemic Hot Spots of Malaria Transmission Occur in Indigenous Comarcas of Panama.

From 2002-2005, Panama experienced a malaria epidemic that has been associated with El Niño Southern Oscillation weather patterns, decreased funding for malaria control, and landscape modification. Case numbers quickly decreased afterward, and Panama is now in the pre-elimination stage of malaria eradication. To achieve this new goal, the characterization of epidemiological risk factors, foci of transmission, and important anopheline vectors is needed. Of the 24,681 reported cases in these analyses (2000-2014), ~62% occurred in epidemic years and ~44% in indigenous comarcas (5.9% of Panama's population). Sub-analyses comparing overall numbers of cases in epidemic and non-epidemic years identified females, comarcas and some 5-year age categories as those disproportionately affected by malaria during epidemic years. Annual parasites indices (APIs; number of cases per 1,000 persons) for Plasmodium vivax were higher in comarcas compared to provinces for all study years, though P. falciparum APIs were only higher in comarcas during epidemic years. Interestingly, two comarcas report increasing numbers of cases annually, despite national annual decreases. Inclusion of these comarcas within identified foci of malaria transmission confirmed their roles in continued transmission. Comparison of species distribution models for two important anophelines with Plasmodium case distribution suggest An. albimanus is the primary malaria vector in Panama, confirmed by identification of nine P. vivax-infected specimen pools. Future malaria eradication strategies in Panama should focus on indigenous comarcas and include both active surveillance for cases and comprehensive anopheline vector surveys.

Anopheles darlingi and Anopheles marajoara (Diptera: Culicidae) susceptibility to pyrethroids in an endemic area of the Brazilian Amazon.

INTRODUCTION: This study aimed to evaluate the susceptibility of Anopheles darlingi Root (1926) and Anopheles marajoara Galvão & Damasceno (1942) to pyrethroids used by the National Malaria Control Program in Brazil. METHODS: Mosquitoes from Amapá, Brazilian Amazon, were assessed for resistance to cypermethrin, deltamethrin, and alpha-cypermethrin. Insecticide-impregnated bottles were used as suggested by the CDC/Atlanta. RESULTS: Diagnostic dose for Anopheles darlingi was 12.5µg/bottle during 30 min of exposure. Concentrations for Anopheles marajoara were 20µg/bottle of cypermethrin and deltamethrin and 12.5µg/bottle of alpha-cypermethrin. CONCLUSIONS: No resistance was recorded for Anopheles darlingi , but Anopheles marajoara requires attention.

Geographic distribution, evolution, and disease importance of species within the Neotropical Anopheles albitarsis Group (Diptera, Culicidae).

The Anopheles albitarsis group of mosquitoes comprises eight recognized species and one mitochondrial lineage. Our knowledge of malaria vectorial importance and the distribution and evolution of these taxa is incomplete. We constructed ecological niche models (ENMs) for these taxa and used hypothesized phylogenetic relationships and ENMs to investigate environmental and ecological divergence associated with speciation events. Two major clades were identified, one north (Clade 1) and one south (Clade 2) of the Amazon River that likely is or was a barrier to mosquito movement. Clade 1 species occur more often in higher average temperature locations than Clade 2 species, and taxon splits within Clade 1 corresponded with a greater divergence of variables related to precipitation than was the case within Clade 2. Comparison of the ecological profiles of sympatric species and sister species support the idea that phylogenetic proximity is related to ecological similarity. Anopheles albitarsis I, An. janconnae, and An. marajoara ENMs had the highest percentage of their predicted suitable habitat overlapping distribution models of Plasmodium falciparum and P. vivax, and warrant additional studies of the transmission potential of these species. Phylogenetic proximity may be related to malaria vectorial importance within the Albitarsis Group.

Risco de transmissão de malária humana em área de implantação de projeto de prospecção mineral, município de Juruti, Estado do Pará / Human malaria transmission risk in an implementation area of mineral prospection, Juruti Municipality, Para State, Brazil

Este estudo objetivou avaliar o risco de transmissão de malária humana em áreas de influência do projeto Juruti no período 2006 a 2008. Um total de 976 mosquitos anofelinos foram capturados por atração humana protegida, identificados e processados para determinação de infectividade pelo teste de imunoensaio (ELISA) e, parte deles (10por cento) para taxa de paridade. Para o inquérito hemoscópico, foram feitas duas coletas (setembro/2007 na comunidade Capiranga e invasão Nova Vitória e março/2008 somente na última) utilizando-se o método da gota expressa (GE). Foram identificadas oito espécies de mosquitos anofelinos, com predomínio da espécie An. albitarsis s.l (76,8por cento) cuja taxa de paridade foi de 9,6por cento. A taxa de infecção foi zero para os primeiros dois anos de estudo e de 0,5por cento em 2008, quando um exemplar de An. albitarsis s.l coletado na comunidade de Santa Maria foi positivo para P. vivax-VK247. O índice de picada homem/hora (IPHH) variou de 0,1 a 8,1. Todas as 148 amostras de sangue foram negativas pela GE. Concluiu-se, portanto, que o risco de transmissão de malária na área estudada é baixo, apesar da presença de mosquitos vetores. Contudo, faz-se necessária vigilância permanente por causa, principalmente, do intenso fluxo migratório gerado pelo projeto.

Fauna anofélica da cidade de Belém, Pará, Brasil: dados atuais e retrospectivos / Anophelines in Belém, Pará, Brazil: current and retrospective data

Relato de coletas de anofelinos realizadas em Belém, Pará, Brasil, de 1995 a 2004, comparando os dados obtidos com os de levantamentos anteriores, feitos a partir da década de 1930. Nesses, vinte espécies haviam sido identificadas: Anopheles albitarsis s.l., An. aquasalis, An. argyritarsis, An. braziliensis, An. darlingi, An. eiseni, An. evansae, An. galvaoi, An. intermedius, An. kompi, An. mediopunctatus, An. nimbus, An. nuneztovari, An. oswaldoi, An. peryassui, An. punctimacula, An. shannoni, An. strodei, An. thomasi e An. triannulatus. Sete (An. argyritarsis, An. eiseni, An. galvaoi, An. kompi, An. nimbus, An. punctimacula e An. thomasi) não são agora registradas. A permanência de tantas outras espécies provavelmente decorre da preservação de áreas de mata no âmbito urbano. Duas delas são consideradas de importância vetorial (An. darlingi e An. aquasalis). Esta última continua sendo a de maior densidade nas coletas (46,26 por cento dos adultos e 99,21 por cento das larvas) e é a única registrada em todos os distritos administrativos. Existe, portanto, risco potencial de transmissão de malária em todo o município.

[Anophelines in Belém, Pará, Brazil: current and retrospective data]. / Fauna anofélica da cidade de Belém, Pará, Brasil: dados atuais e retrospectivos.

We present the results of anopheline captures in Belém, Pará, Brazil, from 1995-2004, and a comparison with captures from 1930-1999. In the earlier period, 20 species were identified: Anopheles albitarsis s.l., An. aquasalis, An. argyritarsis, An. braziliensis, An. darlingi, An. eiseni, An. evansae, An. galvaoi, An. intermedius, An. kompi, An. mediopunctatus, An. nimbus, An. nuneztovari, An. oswaldoi, An. peryassui, An. punctimacula, An. shannoni, An. strodei, An. thomasi, and An. triannulatus. Seven of these species were not found in 1995-2004 (An. argyritarsis, An. eiseni, An. galvaoi, An. kompi, An. nimbus, An. punctimacula, and An. thomasi). The persistence of so many species is probably due to the local preservation of forest areas. Two species are of vectorial importance (An. darlingi and An. aquasalis). An. aquasalis is still the most abundant species (46.26% of adults, 99.21% of larvae) and the only one detected in all capture sites. There is thus a potential risk of malaria transmission in the entire municipality of Belém.

Laboratory colonization of Anopheles aquasalis (Diptera: Culicidae) in Belém, Pará, Brazil.

Anopheles aquasalis Curry, a coastal malaria vector with a Neotropical distribution, was collected from Belém, Pará state, Brazil, and 500 adults per cage were maintained at the Instituto Evandro Chagas insectary at 26 -30 degrees C and 80 -90% RH, where they fed on a 10% domestic sugar solution and blood from white mice. Oviposition of the parental generation (P) occurred in fresh water in dark cups introduced into mosquito cages. After eclosion, 100 larvae per pan were reared in artesian well water (salinity 0.04 g liter(-10) and fed ground fish food until pupation. After force mating in the F1 generation, the eight subsequent generations were free mating. Mean larval mortality was < 1%, and the mean developmental time from eclosion to emergence was 7.7 d (F1), 7.6 d (F2), 8 d (F3), and 7.5 d (F4). The maximum daily production of pupae (from the fourth generation on) occurred on day 6 postoviposition.

[Entomological survey and infectivity during malaria outbreak in the Anajás municipality, Pará State]. / Inquérito entomológico e infectividade durante epidemia de malária no município de Anajás, Estado do Pará.

An entomological survey was conducted in the urban area of Anajás municipality, Para State, in order to verify the risk of malaria transmission. Although the density of Anopheles species was low, the anopheline infectivity rate of 6% demonstrated there is a high risk of infection by the malaria parasites.

Inquérito entomológico e infectividade durante epidemia de malária no município de Anajás, Estado do Pará / Entomological survey and infectivity during malaria outbreak in the Anajás municipality, Pará State

Inquérito entomológico transversal foi conduzido na área urbana no Município de Anajás/PA, para verificar o risco de transmissão malárica. Embora a densidade de Anopheles tenha sido baixa, a taxa de infectividade de 6 por cento e o encontro de espécimes positivos em todos os bairros indicam alto risco de contrair a doença.